Air Filtration FAQ's

For maximum effectiveness, Filtrete™ filters should be changed every three months. However, the life of a filter can depend on the individual conditions of the home. A filter may need to be changed more often if your customer’s home has:

Why does it matter that Filtrete™ filters are "electrostatically charged"?

Filtrete™ electrostatically charged filters have both positively-charged and negatively-charged fibers. The particulates in the air passing through the filter are either positively or negatively charged too—and these charged particles stick to the filter. The charge helps pull more particles from the air than a filter without a charge.

Do Filtrete™ filters remove odors?

Filtrete™ filters help remove allergens from the air, including smoke, smog as well as microscopic particles that can carry viruses, bacteria and odors from the air passing through the filter.

Are Filtrete™ filters antimicrobial?

Filtrete™ filtering material will not support the growth of bacteria, mold, mildew or fungi in normal use. No unnecessary chemicals have been added to the filters.

Do I have to worry about restricted airflow with Filtrete™ filters?

If one of Filtrete™ filters is used for longer than three months, it may begin to restrict airflow or cause the heating/cooling system to malfunction. It also could restrict airflow in some higher-efficiency air conditioning systems. When in doubt, change the filter more frequently.

Will Filtrete™ filters eliminate the need for dusting?

Filtrete™ filters may reduce the need for dusting, but it won't eliminate it. Atmospheric dust consists of a wide variety of particulates ranging in size from 0.001 micron to a relatively large 100 microns. Due to their weight, large particles will settle on furniture long before they will reach a filter.

Some of your filters carry a MERV rating. What does MERV mean?

Minimum Efficiency Reporting Value, or MERV for short, is a filter rating system devised by the American Society of Heating, Refrigeration and Air conditioning Engineers (ASHRAE) to standardize and simplify filter efficiency ratings for the public. The higher the MERV rating, the higher the efficiency of the air filter. Simply stated, a MERV 12 filter will remove smaller particles from the air than a MERV 8 filter.

For the consumer this means that you now have the ability to effectively compare one filterd to another. In general, any MERV 8 or 11 filter will perform about the same as any other MERV 8 or 11 filter, respectively. The MERV rating only applies to efficiency. Additions such as carbon, Lysol anti-bacterial treatment and Arm & Hammer baking soda are value-added benefits and are not an expression of the MERV rating system.

Could you explain the MERV ratings a bit more?

A MERV rating of 13 means the filter is 89-90% minimum efficient at capturing measured particles such as bacteria, tobacco smoke, and particles that make you sneeze.

A MERV rating of 11 means the filter is 80-85% minimum efficient at capturing measured particles such as humidifier dust, lead dust, milled flour, auto emissions and other fumes.

Typical fiberglass throw-away filters are rated at a MERV 4 and below with a 6% minimum efficiency at capturing the measured particles like pollen, sanding dust and larger dust particles.

See the chart below for more detailed information about each MERV rating and the things those filters will trap. The table also shows the efficiency of trapping different sized particles.

Minimum Efficiency Reporting Values - MERV ratings

MERV Value

Average Particle

Size Efficiency

0.3 - 1.0 Microns

Average Particle

Size Efficiency

1.0 - 3.0 Microns

Average Particle

Size Efficiency

3 - 10 Microns

Types of things

these filters

will trap

MERV 1

-

-

Less than 20%

Pollen, Dust mites,

Standing Dust,

Spray Paint Dust,

Carpet Fibers

MERV 2

-

-

Less than 20%

MERV 3

-

-

Less than 20%

MERV 4

-

-

Less than 20%

MERV 5

-

-

20% - 34%

Mold Spores,

Hair Spray,

Fabric Protector,

Cement dust

MERV 6

-

-

35% - 49%

MERV 7

-

-

50% - 69%

MERV 8

-

-

70% - 85%

MERV 9

-

Less than 50%

85% or better

Humidifier Dust,

Lead Dust,

Auto Emissions,

Milled Flour

MERV 10

-

50% - 64%

85% or better

MERV 11

-

65% - 79%

85% or better

MERV 12

-

80% - 89%

90% or better

MERV 13

Less than 75%

90% or better

90% or better

Bacteria,

Most Tobacco

Smoke,

Proplet Nuceli (sneeze)

MERV 14

75% - 84%

90% or better

90% or better

MERV 15

85% - 94%

90% or better

90% or better

MERV 16

95% or better

90% or better

90% or better

Please contact licensee of Filtrete™ filters for claim substantiation and warranty information related to the basic air filters purchased on this website. 3M is not responsible for providing claim and warranty support for these basic products.